Testing Seaweed for Quality

We annually test our sea vegetables following each harvest season and throughout the year to ensure they're free of food pathogens and harmful levels of naturally occurring or human origin contaminants such as heavy metals, pesticides, petroleum residues, and radiation.  Annual test results are posted below.

Why We Test

What We Test For

Microbes

We regularly screen our products to ensure they meet food safety standards. We test for total bacterial counts, mold & yeast, coliform bacteria and pathogenic E. coli, and food pathogens such as Salmonella and Listeria.  We have never detected any of these common foodborne pathogens in over 30 years of testing. This is because dried sea vegetables contain natural sea salts and very little moisture, which makes them inhospitable for microbial growth and gives them an extended shelf life. Like other raw natural foods, dried seaweed is not entirely sterile, so rehydrated seaweed should be refrigerated during and after reconstitution. 

We occasionally get questions from customers wondering if their seaweed is moldy.  Usually, the white or grayish powder they observe is a mixture of precipitated salts and sugars.  Our FAQs and this downloadable document titled "Moldy Seaweed" have more information on this topic.

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Pesticides/Herbicides

Widely used in agriculture and by property owners, and consequently found as residues on many agricultural crops. We use a protocol endorsed by the USDA National Organic Program (NOP) for testing certified organic produce. Testing is done annually by us and at random by our certifying agency (OCIA); our test results are posted below as NOP panel.

Petroleum Residues

Tested as Polycyclic Aromatic Hydrocarbons (PAHs). This screen verifies our seaweed doesn't have harmful levels of gasoline and oil combustion residues from surface runoff or boats. Seaweed harvests are annually tested and results posted below as PAH's.

Heavy Metals

Our labs use Inductively Coupled Plasma - Mass Spectrometry (ICP-MS) to detect and quantify trace levels of cadmium, lead, mercury, and inorganic forms of arsenic in our seaweed. These elements are widely distributed in the world’s oceans from both natural and human sources. Seaweed harvests are annually tested and the results, along with more detail on heavy metals, are posted below. 

Radioactivity

During and after the 2011 Fukushima nuclear catastrophe, customers became concerned that even seaweed as far away from the disaster as Maine could have become contaminated, and we’ve been annually testing ever since. Test results are found below. 

How We Test

Testing is done every winter after the harvest has been dried and stored. We take care to collect composite samples representative of each species, growing area, and form (leaf or milled). We don’t test every single batch or product, but we do test a representative of every species and growing area.  For example, we may test dulse flakes but not powdered dulse because the two products come from the same species and area. In this case, test results for dulse flakes also apply to the powdered form.

Testing is done through accredited third-party labs. Seaweed has a  complicated matrix that's unlike many other foods, and it's important that labs understand this. Our contract labs use analytical methods refined over many decades by scientists from around the world and  validated by the EPA, FDA and global certification organizations before being approved for food testing. We work closely with testing labs to remain current with the latest changes and refinements to test methods. Some of our testing labs include Northeast Laboratories, Bigelow, and Eurofins.

Disclaimer

Seaweed is a traditional whole food that's been eaten by people  around the world for many thousands of years with healthy results. However, every person is unique and we are unable to predict your body's response. There may be elements of these plants not suitable for your particular biochemistry or condition. Only you can determine what's best for you, in consultation with your healthcare practitioner. The seaweeds we sell are wild harvested, uncultivated marine algae. Naturally occurring fluctuations in the sea plants occur due to season, climate, tidal flow and time of harvest. The information we present on this website is believed to be accurate and reliable, but the testing is not carried out by Maine Coast Sea Vegetables and it is not guaranteed as a condition of sale. Maine Coast Sea Vegetables makes no warranty, either express or implied, and assumes no liability for this information or the products described.

Heavy Metals in Seaweed

Customers sometimes ask why we test our Certified Organic sea vegetables for heavy metals, or why some products bear a "Proposition 65" warning about lead and cadmium.  The reason for both is that as seaweed absorbs minerals from the ocean that are essential for human health, it also absorbs certain heavy metals that can harm human health.  Testing helps both us and our customers make informed choices to safeguard health.

Minerals and elements, including heavy metals, are widely distributed throughout the world's oceans from natural processes such as weathering of the earth’s crust and atmospheric deposition, as well as from human industrial activity. Our seaweed comes from remote and wild areas far from big cities and industry, and Organic Certification ensures it isn't harvested near local sources of contamination such as boat marinas or municipal outfalls.  However, because heavy metals are so ubiquitous in the environment, Organic Certification alone doesn't guarantee purity for seaweed or any other food.

Annual testing helps us determine whether products require a California Proposition 65 warning, and posting the data on our website helps our customers make informed choices.  Scientists have studied the topic of heavy metals in seaweed for many years, and our assessment is that the numerous health and nutrition benefits of sea vegetables far outweigh the risk posed by the low levels of heavy metals they contain. However, we respect that others, for personal health reasons, may feel otherwise.  This is why we test and post the results. For more information on this topic, please see the Heavy Metals FAQ in the section about environmental concerns.  

Radioactivity Testing in Seaweed

We started testing seaweed for radioactivity in 2011 in response to the Fukushima, Japan nuclear catastrophe, and we haven't stopped since. Humans have released radiation into the environment, whether intentionally or accidentally, ever since the US first tested atomic bombs in 1945. Because eating seaweed offers some protection from radiation, it’s important to ensure the seaweed itself is free of harmful radioactive isotopes.  This topic is further addressed in our FAQs.

We used the University of Maine Department of Physics lab from 2011 to 2019 to test for radiation. In 2020 we moved to using a commercial lab for this testing. Test results are given as Bq per kg, which is a measure of the activity of a radioactive isotope.  Japanese standards for acceptable activity levels in food and water are among the strictest in the world, and they call for less than 100 Bq/kg in general foodstuffs and less than 10 Bq/kg in water.  The lower threshold for water is because it's essential for life, has no substitute, and has a high rate of consumption.

Our most recent test results are shown below. Past results along with more detail about testing are found in this downloadable PDF "Summary of Radiation Testing 2011-2019". So far, harmful levels of radioactive isotopes have never been detected in any of our seaweeds.

Don't use a Geiger Counter to Detect Radiation in Seaweed!